MySQL query to replace null value with empty string in several columns while fetching data

For this, you can use IFNULL() or COALESCE(). Let us first create a table −

mysql> create table DemoTable1849
     (
     ClientFirstName varchar(20),
     ClientLastName varchar(20)
     );
Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1849 values('John',NULL);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1849 values(NULL,'Miller');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1849 values(NULL,NULL);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1849 values('Chris','Brown');
Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1849;

This will produce the following output −

+-----------------+----------------+
| ClientFirstName | ClientLastName |
+-----------------+----------------+
| John            |           NULL |
| NULL            |         Miller |
| NULL            |           NULL |
| Chris           |          Brown |
+-----------------+----------------+
4 rows in set (0.00 sec)

Here is the query to replace null value with empty string in several columns while fetching data −

mysql> select ifnull(ClientFirstName,'') as ClientFirstName,ifnull(ClientLastName,'') as ClientLastName from DemoTable1849;

This will produce the following output −

+-----------------+----------------+
| ClientFirstName | ClientLastName |
+-----------------+----------------+
| John            |                |
|                 |         Miller |
|                 |                |
| Chris           |          Brown |
+-----------------+----------------+
4 rows in set (0.00 sec)